GeForce GTX 275 vs Radeon HD 4890 2GB

Intro

Compare those specs to the Radeon HD 4890 2GB, which comes with a clock speed of 1000 MHz and a GDDR5 memory frequency of 975 MHz. It also uses a 256-bit memory bus, and makes use of a 55 nm design. It features 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4890 2GB		190 Watts
GeForce GTX 275		219 Watts
	Difference: 29 Watts (15%)

Memory Bandwidth

Theoretically, the GeForce GTX 275 should perform a bit faster than the Radeon HD 4890 2GB overall. (explain)

GeForce GTX 275		127008 MB/sec
Radeon HD 4890 2GB		124800 MB/sec
	Difference: 2208 (2%)

Texel Rate

The GeForce GTX 275 should be quite a bit (approximately 27%) more effective at texture filtering than the Radeon HD 4890 2GB. (explain)

GeForce GTX 275		50640 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 10640 (27%)

Pixel Rate

The GeForce GTX 275 is a small bit (approximately 11%) better at anti-aliasing than the Radeon HD 4890 2GB, and should be able to handle higher resolutions without slowing down too much. (explain)

GeForce GTX 275		17724 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 1724 (11%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of information (measured in MB per second) that can be moved past the external memory interface within a second. The number is worked out by multiplying the bus width by the speed of its memory. In the case of DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.